1. Installation / Ease of use - both for the host and programmer and for the nit-wit you are building it for.2. Security / Vulnerability - being open source, these all have been, and will continue to be, exploitable... which is the most on top of their patches and makes them easy to update.3. Front End / Back End - User registration, user levels, boards, shoutboxes, etc... how well does it all flow?4. Design - Are there nice templates or do you have to have a doctorate in CSS cryptology to decipher the themes and stylesheets?5. Flexibility - Can this thing be overhauled, updated and rehashed in the event the site changes direction?